Thousands of tubes of fake Colgate toothpaste have been recalled by two major retailers.
Sainsbury's and Boots were duped into selling the counterfeit product between 28 November and 5 December.
It was labelled Colgate Cavity Protection and came in 100ml tubes.
The supermarket giant said it had written to 17,000 customers and put recall notices in branches.
Last year in the US, batches of fake Colgate were found to contain the chemical diethylene glycol, which is an ingredient in anti-freeze. However, Sainsbury's said today that there were "no health risks" over the fake product found in stores.
A spokesman for the supermarket said: "We believe there are no health risks associated with using the counterfeit toothpaste but, as it is not a genuine Colgate product, we removed the affected tubes from our stores immediately.
"At the same time we put notices up at point of sale and on the customer service desk, and have written to 17,000 customers asking them to return the product for a full refund. We have also notified the trading standards authorities.
"We believed the supplier we bought the toothpaste from was reputable, and we are carrying out a full investigation into how this has occurred so that we can prevent it from happening again."
Boots said it has contacted customers who use loyalty cards and put notices up in branches.
A spokeswoman said: "We take the health and well-being of our customers extremely seriously.
"As soon as we were made aware of a possible issue with this product, it was immediately withdrawn from sale.
"Customers that we know bought this product via our Advantage Card records have been contacted and we have issued a customer recall notice to be displayed in our stores."
Sainsbury's said the fake toothpaste was laboratory-tested and found not to contain anything toxic, and insisted the product was bought "in good faith".
Boots simply said the product was "inspected on delivery" but pledged: "We will be reviewing our procedures in light of this issue."
Its spokeswoman added: "This particular batch of toothpaste was bought via a wholesale supplier. We are taking this matter very seriously and are currently discussing the matter with them."
They refused to name the wholesaler or rule out trading with the same company in future.Reuse content